package com.github.mmin18.widget;

import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;

public class AndroidStockBlurImpl implements BlurImpl {
	private Paint mPaint;
	private Canvas mCanvas;

	@Override
	public boolean prepare(View view, Bitmap buffer, float radius) {
		mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
		mCanvas = new Canvas();
		return true;
	}

	@Override
	public void release() {
		mPaint = null;
		mCanvas = null;
	}

	@Override
	public void blur(Bitmap bitmapIn, Bitmap bitmapOut) {
		if (bitmapIn == null || bitmapOut == null) return;
		fastBlur(bitmapIn, bitmapOut, 20); // 20为模糊半径，可根据实际radius参数调整
	}

	// FastBlur算法实现
	private void fastBlur(Bitmap sentBitmap, Bitmap outBitmap, int radius) {
		if (radius < 1) {
			return;
		}
		Bitmap bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
		int w = bitmap.getWidth();
		int h = bitmap.getHeight();

		int[] pix = new int[w * h];
		bitmap.getPixels(pix, 0, w, 0, 0, w, h);

		int wm = w - 1;
		int hm = h - 1;
		int wh = w * h;
		int div = radius + radius + 1;

		int[] r = new int[wh];
		int[] g = new int[wh];
		int[] b = new int[wh];
		int rsum, gsum, bsum, x, y, i, p1, p2, yi;
		int[] vmin = new int[Math.max(w, h)];

		int divsum = (div + 1) >> 1;
		divsum *= divsum;
		int[] dv = new int[256 * divsum];
		for (i = 0; i < 256 * divsum; i++) {
			dv[i] = (i / divsum);
		}

		int yw = 0, yi2 = 0;

		int[][] stack = new int[div][3];
		int stackpointer;
		int stackstart;
		int[] sir;
		int rbs;
		int routsum, goutsum, boutsum;
		int rinsum, ginsum, binsum;

		for (y = 0; y < h; y++) {
			rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
			for (i = -radius; i <= radius; i++) {
				int p = pix[yi2 + Math.min(wm, Math.max(i, 0))];
				sir = stack[i + radius];
				sir[0] = (p & 0xff0000) >> 16;
				sir[1] = (p & 0x00ff00) >> 8;
				sir[2] = (p & 0x0000ff);
				rbs = radius + 1 - Math.abs(i);
				rsum += sir[0] * rbs;
				gsum += sir[1] * rbs;
				bsum += sir[2] * rbs;
				if (i > 0) {
					rinsum += sir[0];
					ginsum += sir[1];
					binsum += sir[2];
				} else {
					routsum += sir[0];
					goutsum += sir[1];
					boutsum += sir[2];
				}
			}
			stackpointer = radius;

			for (x = 0; x < w; x++) {
				r[yi2] = dv[rsum];
				g[yi2] = dv[gsum];
				b[yi2] = dv[bsum];

				rsum -= routsum;
				gsum -= goutsum;
				bsum -= boutsum;

				stackstart = stackpointer - radius + div;
				sir = stack[stackstart % div];

				routsum -= sir[0];
				goutsum -= sir[1];
				boutsum -= sir[2];

				if (y == 0) {
					vmin[x] = Math.min(x + radius + 1, wm);
				}
				int p = pix[yw + vmin[x]];
				sir[0] = (p & 0xff0000) >> 16;
				sir[1] = (p & 0x00ff00) >> 8;
				sir[2] = (p & 0x0000ff);

				rinsum += sir[0];
				ginsum += sir[1];
				binsum += sir[2];

				rsum += rinsum;
				gsum += ginsum;
				bsum += binsum;

				stackpointer = (stackpointer + 1) % div;
				sir = stack[(stackpointer) % div];

				routsum += sir[0];
				goutsum += sir[1];
				boutsum += sir[2];

				rinsum -= sir[0];
				ginsum -= sir[1];
				binsum -= sir[2];

				yi2++;
			}
			yw += w;
		}

		for (x = 0; x < w; x++) {
			rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
			int yp = -radius * w;
			for (i = -radius; i <= radius; i++) {
				yi = Math.max(0, yp) + x;
				sir = stack[i + radius];
				sir[0] = r[yi];
				sir[1] = g[yi];
				sir[2] = b[yi];
				rbs = radius + 1 - Math.abs(i);
				rsum += r[yi] * rbs;
				gsum += g[yi] * rbs;
				bsum += b[yi] * rbs;
				if (i > 0) {
					rinsum += sir[0];
					ginsum += sir[1];
					binsum += sir[2];
				} else {
					routsum += sir[0];
					goutsum += sir[1];
					boutsum += sir[2];
				}
				if (i < hm) {
					yp += w;
				}
			}
			yi = x;
			stackpointer = radius;
			for (y = 0; y < h; y++) {
				pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];
				rsum -= routsum;
				gsum -= goutsum;
				bsum -= boutsum;
				stackstart = stackpointer - radius + div;
				sir = stack[stackstart % div];
				routsum -= sir[0];
				goutsum -= sir[1];
				boutsum -= sir[2];
				if (x == 0) {
					vmin[y] = Math.min(y + radius + 1, hm) * w;
				}
				p1 = x + vmin[y];
				sir[0] = r[p1];
				sir[1] = g[p1];
				sir[2] = b[p1];
				rinsum += sir[0];
				ginsum += sir[1];
				binsum += sir[2];
				rsum += rinsum;
				gsum += ginsum;
				bsum += binsum;
				stackpointer = (stackpointer + 1) % div;
				sir = stack[stackpointer];
				routsum += sir[0];
				goutsum += sir[1];
				boutsum += sir[2];
				rinsum -= sir[0];
				ginsum -= sir[1];
				binsum -= sir[2];
				yi += w;
			}
		}
		outBitmap.setPixels(pix, 0, w, 0, 0, w, h);
	}
}
